Holley 1920 Carb question 225 - 6

The Holley 1920 carb on my 64 Barracuda is dumping gasoline out onto the intake manifold. After pulling and cleaning the exterior, there is a small hole or chip on the bottom 'cast tube' running along the bowl on the back side.

It looks like it is actually a drilled hole, but I am just waiting for the dumped gas to ignite.

Is this hole supposed to be there? is this the curb idle vent I read about?

I sent Holley Tech the question on Sunday and they have chosen not to answer yet.

This is holding up putting the car back on the road and is killing me.

Lou